African journal of aquatic science [elektronický zdroj]. Grahamstown, South Africa : National Inquiry Services Centre. Mode of access: World Wide Web. Available on Internet: <http://sfx.jib.cz/sfxlcl3?url_ver=Z39.88-2004&ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&rfr_id=info:sid/sfxit.com:opac_856&url_ctx_fmt=info:ofi/fmt:kev:mtx:ctx&sfx.ignore_date_threshold=1&rft.object_id=111057011093036&svc_val_fmt=info:ofi/fmt:kev:mtx:sch_svc&>